github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/pkg/sql/sqlbase/roundtrip_format.go (about)

     1  // Copyright 2020 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  package sqlbase
    12  
    13  import (
    14  	"github.com/cockroachdb/cockroach/pkg/sql/parser"
    15  	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
    16  	"github.com/cockroachdb/cockroach/pkg/sql/types"
    17  )
    18  
    19  // ParseDatumStringAs parses s as type t. This function is guaranteed to
    20  // round-trip when printing a Datum with FmtExport.
    21  func ParseDatumStringAs(t *types.T, s string, evalCtx *tree.EvalContext) (tree.Datum, error) {
    22  	switch t.Family() {
    23  	// We use a different parser for array types because ParseAndRequireString only parses
    24  	// the internal postgres string representation of arrays.
    25  	case types.ArrayFamily, types.CollatedStringFamily:
    26  		return parseAsTyp(evalCtx, t, s)
    27  	default:
    28  		return tree.ParseAndRequireString(t, s, evalCtx)
    29  	}
    30  }
    31  
    32  // ParseDatumStringAsWithRawBytes parses s as type t. However, if the requested type is Bytes
    33  // then the string is returned unchanged. This function is used when the input string might be
    34  // unescaped raw bytes, so we don't want to run a bytes parsing routine on the input. Other
    35  // than the bytes case, this function does the same as ParseDatumStringAs but is not
    36  // guaranteed to round-trip.
    37  func ParseDatumStringAsWithRawBytes(
    38  	t *types.T, s string, evalCtx *tree.EvalContext,
    39  ) (tree.Datum, error) {
    40  	switch t.Family() {
    41  	case types.BytesFamily:
    42  		return tree.NewDBytes(tree.DBytes(s)), nil
    43  	default:
    44  		return ParseDatumStringAs(t, s, evalCtx)
    45  	}
    46  }
    47  
    48  func parseAsTyp(evalCtx *tree.EvalContext, typ *types.T, s string) (tree.Datum, error) {
    49  	expr, err := parser.ParseExpr(s)
    50  	if err != nil {
    51  		return nil, err
    52  	}
    53  	semaCtx := tree.MakeSemaContext()
    54  	typedExpr, err := tree.TypeCheck(evalCtx.Context, expr, &semaCtx, typ)
    55  	if err != nil {
    56  		return nil, err
    57  	}
    58  	datum, err := typedExpr.Eval(evalCtx)
    59  	return datum, err
    60  }